I connected Autofac to my ASP.NET CORE WEB-API application.
Registered two implementations of IService in the container by keys (enum).
Through the IComponentContext container, using the key, I get one of the implementations in the Get method of the controller (BotController):
_container.ResolveKeyed ((ServiceEnum) serviceType).
I read on the forum that it is not correct to use IComponentContext.
Questions:
-1. Why is it wrong?
-2. If not correct how can I resolve Named and Keyed implementations?
Example controller:
[ApiController]
[Route("api/message/update")]
public class BotController : Controller
{
private readonly IMainDbConnection _connection;
private readonly IComponentContext _container;
public BotController(IMainDbConnection connection, IComponentContext container)
{
_connection = connection;
_container = container;
}
[HttpGet]
public IActionResult Get(int serviceType)
{
var service = _container.ResolveKeyed<IService>((ServiceEnum) serviceType);
var result = service.Get(serviceType.ToString());
return Ok(result);
}
}
Related
I am migrating an ASP.NET MVC application to ASP.NET Core 3.1.
And I have a code to check if the session was timed out in my controller, like this:
if (Session.IsNewSession) {
How can I check it in ASP.NET Core?
Thanks
The default implementation of ISession is DistributedSession. This does not expose any property for IsNewSession although its constructor accepts a parameter named isNewSessionKey. So you can use reflection to get that private field of _isNewSessionKey to check it. But that way is not very standard, the name may be changed in future without notifying you any design-time error.
You have several points to intercept and get the info here. The first point is to create a custom ISessionStore (default by DistributedSessionStore) to intercept the call to ISessionStore.Create which gives access to isNewSessionKey. You can capture that value into a request feature just like how the framework set the ISessionFeature after creating the session. Here's the code:
//create the feature interface & class
public interface ISessionExFeature {
bool IsNewSession { get; }
}
public class SessionExFeature : ISessionExFeature {
public SessionExFeature(bool isNewSession){
IsNewSession = isNewSession;
}
public bool IsNewSession { get; }
}
//the custom ISessionStore
public class CustomDistributedSessionStore : DistributedSessionStore, ISessionStore
{
readonly IHttpContextAccessor _httpContextAccessor;
public CustomDistributedSessionStore(IDistributedCache cache,
ILoggerFactory loggerFactory,
IHttpContextAccessor httpContextAccessor) : base(cache, loggerFactory)
{
_httpContextAccessor = httpContextAccessor;
}
ISession ISessionStore.Create(string sessionKey, TimeSpan idleTimeout, TimeSpan ioTimeout, Func<bool> tryEstablishSession, bool isNewSessionKey)
{
var httpContext = _httpContextAccessor.HttpContext;
if(httpContext != null)
{
var sessionExFeature = new SessionExFeature(isNewSessionKey);
httpContext.Features.Set<ISessionExFeature>(sessionExFeature);
}
return Create(sessionKey, idleTimeout, ioTimeout, tryEstablishSession, isNewSessionKey);
}
}
//register the custom ISessionStore inside Startup.ConfigureServices
services.Replace(new ServiceDescriptor(typeof(ISessionStore), typeof(CustomDistributedSessionStore), ServiceLifetime.Transient));
//an extension method to help get the ISessionExFeature conveniently
public static class SessionExFeatureHttpContextExtensions {
public static bool HasNewSession(this HttpContext context){
return context.Features.Get<ISessionExFeature>()?.IsNewSession ?? false;
}
}
To use it in your code:
if (HttpContext.HasNewSession()) {
//...
}
Another point to intercept and get the info is customize both the ISessionStore and ISession. Which means you create a sub class of DistributedSession and expose the property for IsNewSession. That may require more code but it looks more like the old way of getting the info (directly from the Session not kind of via an extension method on HttpContext).
I've been following the NServiceBus samples, specifically for how to use an entity framework (core) DbContext integrated with Sql Persistence so that I can save dbcontext state changes along with the outbox messages. This is the sample: https://docs.particular.net/samples/entity-framework-core/
I've modified the unit of work code a little to support creation of an aspnet core DI scoped DbContext. The relevant code follows:
public class UnitOfWork<TDbContext>
where TDbContext : DbContext
{
private Func<SynchronizedStorageSession, IServiceProvider, TDbContext> _contextFactory;
private TDbContext _context;
private IServiceProvider _serviceProvider;
public UnitOfWork(Func<SynchronizedStorageSession, IServiceProvider, TDbContext> contextFactory, IServiceProvider serviceProvider)
{
_contextFactory = contextFactory;
_serviceProvider = serviceProvider;
}
public TDbContext GetDataContext(SynchronizedStorageSession storageSession)
{
if (_context == null)
{
_context = _contextFactory(storageSession, _serviceProvider);
}
return _context;
}
}
public class UnitOfWorkSetupBehavior<TDbContext> : Behavior<IIncomingLogicalMessageContext>
where TDbContext : DbContext
{
private readonly Func<SynchronizedStorageSession, IServiceProvider, TDbContext> _contextFactory;
private readonly IServiceScopeFactory _serviceScopeFactory;
public UnitOfWorkSetupBehavior(Func<SynchronizedStorageSession, IServiceProvider, TDbContext> contextFactory, IServiceScopeFactory serviceScopeFactory)
{
_contextFactory = contextFactory;
_serviceScopeFactory = serviceScopeFactory;
}
public override async Task Invoke(IIncomingLogicalMessageContext context, Func<Task> next)
{
using (var scope = _serviceScopeFactory.CreateScope())
{
var uow = new UnitOfWork<TDbContext>(_contextFactory, scope.ServiceProvider);
context.Extensions.Set(uow);
await next().ConfigureAwait(false);
context.Extensions.Remove<UnitOfWork<TDbContext>>();
}
}
}
public static class EndpointConfigurationExtensions
{
public static void RegisterUnitOfWork<TDbContext>(this EndpointConfiguration endpointConfiguration, IServiceScopeFactory serviceScopeFactory)
where TDbContext : DbContext
{
var pipeline = endpointConfiguration.Pipeline;
pipeline.Register(new UnitOfWorkSetupBehavior<TDbContext>((storageSession, serviceProvider) =>
{
var dbConnection = storageSession.SqlPersistenceSession().Connection;
var dbContextFactory = serviceProvider.GetService<IDbContextConnectionFactory<TDbContext>>();
var dbContext = dbContextFactory.GetDbContext(dbConnection);
//Use the same underlying ADO.NET transaction
dbContext.Database.UseTransaction(storageSession.SqlPersistenceSession().Transaction);
//Call SaveChanges before completing storage session
storageSession.SqlPersistenceSession().OnSaveChanges(x => dbContext.SaveChangesAsync());
return dbContext;
}, serviceScopeFactory), "Sets up unit of work for the message");
}
}
public static class UnitOfWorkContextExtensions
{
public static TDbContext DataContext<TDbContext>(this IMessageHandlerContext context)
where TDbContext : DbContext
{
var uow = context.Extensions.Get<UnitOfWork<TDbContext>>();
return uow.GetDataContext(context.SynchronizedStorageSession);
}
}
For this to work the behavior needs an injected IServiceScopeFactory.
Now all examples I've been able to find of behavior registration only show the type manually instantiated and passed in to the endpointconfiguration's pipeline.
Is there a way to either gain access to an IServiceScopeFactory via the behavior's Invoke method (maybe by the context via some extension perhaps?), or is it possible to register the behavior itself such that I can construct it with services created by the DI container?
FYI I took a look at this Q&A which gave me the idea of injecting the IServiceScopeFactory. Unfortunately, the answer doesn't show how to actually get an instance of the interface.
You would use context.builder.Build<T>(); within the Invoke method to resolve any objects like IServiceScopeFactory.
https://docs.particular.net/samples/multi-tenant/di/
Make sure that the IServiceScopeFactory is registered in the DI container. For example, during your endpoint initialization:
endpointConfiguration.RegisterComponents(registration: x =>
{
x.ConfigureComponent<IServiceScopeFactory>(yourServiceScopeFactory);
});
https://docs.particular.net/nservicebus/dependency-injection/
You can also do this by creating a Feature
https://docs.particular.net/nservicebus/pipeline/features
I have a WebApi service that I am trying to add authentication to using Ninject BindHttpFilter.
Using the BindHttpFilter allows me to bind the authentication filter to a specific attribute. The AuthenticationFilter takes a constructor parameter (IAuthenticationService) which itself is created by Ninject.
kernel.BindHttpFilter<AuthenticationHttpFilter>(System.Web.Http.Filters.FilterScope.Action)
.WhenActionMethodHas<AuthenticationFilterAttribute>()
.WithConstructorArgument("service", x => x.Kernel.Get<IAuthenticationService>());
The concrete implementation of AuthenticationService takes a constructor parameter INonceRepository which is injected via Ninject:
public AuthenticationService(INonceRepository nonceRepository, ...)
The concrete implementation of NonceRepository takes a constructor ISession which is injected via Ninject:
public NonceRepository(ISession session)
Here is what the Ninject bindings look like:
kernel.Bind<INonceRepository>().To<NonceRepository>();
kernel.Bind<IAuthenticationService>().To<AuthenticationService>()
var session = sessionFactory.OpenSession();
Bind<ISession>().ToMethod(c => session).InRequestScope();
When the code runs the concrete implementation of AuthenticationService is only instantiated once and therefore NonceRepositiory is only instantiated once. This means that the ISession is valid and Open the first request but the ISession is closed on the second call and the constructor of AuthenticationService is never called the second time. It seems like it is a scoping issue but I can't figure out what doesn't have the correct scoping to make AuthenticationService get recreated per request.
I've tried to change the BindHttpScope request from FilterScope.Controller to FilterScope.Action (thinking that would cause the scope of AuthenticationService to be that it was create per Action call) but that didn't solve it.
Here is what the the interesting points of code looks like:
public class AuthenticationHttpFilter : IAuthenticationFilter
{
private readonly IAuthenticationService authenticationService;
public AuthenticationHttpFilter(IAuthenticationService service)
{
this.authenticationService = service;
}
public bool AllowMultiple { get; private set; }
public Task AuthenticateAsync(HttpAuthenticationContext authenticationContext, CancellationToken cancellationToken)
{
authenticationService.DoAuth();
return Task.FromResult(0);
}
public Task ChallengeAsync(HttpAuthenticationChallengeContext authenticationChallengeContext, CancellationToken cancellationToken)
{
...
}
}
public class AuthenticationService : IAuthenticationService
{
private readonly INonceRepository nonceRepo;
public AuthenticationService(INonceRepository nonceRepo){...}
public void DoAuth()
{
this.nonceRepo.Add(...);
}
}
public class NonceRepository : INonceRepository
{
private readonly ISession _session;
public NonceRepository(ISession session)
{
this._session = session;
}
public void Add(Nonce nonce)
{
this._session.Save(nonce);
}
}
I found that that when I am using WebApi 2, everything works fine. It behaves in RequestScope like I would expect. However, when using MVC 5, the filter stays cached in the pipeline, which keeps the constructor argument in a "Singleton" scope.
I fixed this problem by reaching into the configuration of the actionContext as such:
[AttributeUsage(AttributeTargets.Method | AttributeTargets.Class, AllowMultiple = false, Inherited = true)]
public class EventGridFilterAttribute : ActionFilterAttribute
{
private readonly Type serviceType = typeof(IEventGridService);
public EventGridFilterAttribute()
{
}
public override async Task OnActionExecutedAsync(HttpActionExecutedContext actionExecutedContext, CancellationToken cancellationToken)
{
var service = actionExecutedContext?.ActionContext?.ControllerContext?.Configuration?.DependencyResolver?.GetService(serviceType) as IEventGridService;
if (service != null && actionExecutedContext.Exception == null)
{
await service.PublishEventsAsync();
}
await base.OnActionExecutedAsync(actionExecutedContext, cancellationToken);
}
}
My dependency injector is saved here.
GlobalConfiguration.Configuration.DependencyResolver = new NinjectDependencyResolver(kernel);
I also do not use the BindHttpFilter, but register my filter like a normal filter.
public static void RegisterGlobalFilters(GlobalFilterCollection filters)
{
filters.Add(new EventGridFilterAttribute());
}
I have an ASP.NET MVC app with SignalR and WebAPI. The app uses Ninject for dependency injection, but apparently SignalR and WebAPI are getting different kernels, so it fails to share a singleton object that should be shared for all the application.
I can see clearly in the log how an instance is created when SignalR gets a connection request, and other when WebAPI gets a request.
I want to have the same Ninject kernel shared among these three elements, so I can have unique singletons.
This is what I have done so far:
The first thing I have done is creating a NinjectModule declaring the binding:
public class MyDependencyModule: NinjectModule
{
public override void Load()
{
var binding = Bind<MustBeSingleton>().ToSelf();
binding.OnActivation((ctx, o) =>
{
Debug.Print("Registering item " + o.GetHashCode());
HostingEnvironment.RegisterObject(o);
});
binding.OnDeactivation(o =>
{
Debug.Print("Unregistering game connection " + o.GetHashCode());
});
binding.InSingletonScope();
}
}
I have also created a wrapper for Ninject in order to plug it in WebAPI:
public class NinjectDependencyScope : IDependencyScope
{
private IResolutionRoot resolver;
internal NinjectDependencyScope(IResolutionRoot resolver)
{
this.resolver = resolver;
}
public void Dispose()
{
IDisposable disposable = resolver as IDisposable;
if (disposable != null)
disposable.Dispose();
resolver = null;
}
public object GetService(Type serviceType)
{
if (resolver == null)
throw new ObjectDisposedException("this", "This scope has already been disposed");
return resolver.TryGet(serviceType);
}
public IEnumerable<object> GetServices(Type serviceType)
{
if (resolver == null)
throw new ObjectDisposedException("this", "This scope has already been disposed");
return resolver.GetAll(serviceType);
}
}
public class NinjectDependencyResolver : NinjectDependencyScope, IDependencyResolver
{
private IKernel kernel;
public NinjectDependencyResolver(IKernel kernel)
: base(kernel)
{
this.kernel = kernel;
}
public IDependencyScope BeginScope()
{
return new NinjectDependencyScope(kernel.BeginBlock());
}
}
Also, I have created another wrapper for SignalR:
public class SignalRNinjectDependencyResolver : DefaultDependencyResolver
{
private readonly IKernel _kernel;
public SignalRNinjectDependencyResolver(IKernel kernel)
{
_kernel = kernel;
}
public override object GetService(Type serviceType)
{
return _kernel.TryGet(serviceType) ?? base.GetService(serviceType);
}
public override IEnumerable<object> GetServices(Type serviceType)
{
return _kernel.GetAll(serviceType).Concat(base.GetServices(serviceType));
}
}
Then I have created a Ninject kernel that does all the config:
public class ApplicationDependencies:StandardKernel
{
public ApplicationDependencies()
:base(new MyDependencyModule())
{
System.Web.Http.GlobalConfiguration.Configuration.DependencyResolver = new NinjectDependencyResolver(this);
Microsoft.AspNet.SignalR.GlobalHost.DependencyResolver = new SignalRNinjectDependencyResolver(this);
}
}
The MVC application, uses NinjectHttpApplication as base class, so I indicate the kernel that must be used this way:
public class MvcApplication : Ninject.Web.Common.NinjectHttpApplication
{
protected override Ninject.IKernel CreateKernel()
{
return new ApplicationDependencies();
}
}
Also, in the SignalR configuration I specify the Resolver:
public class Startup
{
public void Configuration(IAppBuilder app)
{
app.MapSignalR<MyPersistentConnection>("/updates", new ConnectionConfiguration()
{
Resolver = GlobalHost.DependencyResolver
});
}
}
(I have tried also without specifying the resolver, and it does not work either).
Any idea?
Cheers.
I found the answer in another post: Singleton Scope binding not working as intended
Rather than binding as a singleton, "ToConstant" must be used:
var binding = Bind<MustBeSingleton>().ToConstant(new MustBeSingleton());
I have created a simple demo project with ASP.NET MVC, WebAPI and SignalR using the same dependency injection context.
https://drive.google.com/file/d/0B52OsuSSsroNX0I5aWFFb1VrRm8/edit?usp=sharing
The web app, contains a single page that shows the AppDomain and GetHashCode of an object that is supposed to be unique across the three frameworks, giving a result similar to:
Dependency Test
Framework IMySingletonService instance
MVC AppDomainId:2 / HashCode:5109846
WebAPI AppDomainId:2 / HashCode:5109846
SignalR AppDomainId:2 / HashCode:5109846
Other problem was, that Ninject was disposing my singleton because was IDisposable. I don't really understand why this happens, but that is another war.
Cheers.
In order keep this 3 things working.. you should check these references out:
Web API + Ninject
http://www.peterprovost.org/blog/2012/06/19/adding-ninject-to-web-api/
SignalR + Ninject https://github.com/SignalR/SignalR/wiki/Extensibility (last part:
When using ASP.NET MVC, configure SignalR first, then ASP.NET MVC)
For the second one, I refactored a little bit, since I need the kernel for SignalR Dependency Resolver
// Route SignalR.
GlobalHost.DependencyResolver = NinjectWebCommon.GetSignalrResolver();
RouteTable.Routes.MapHubs();
I defined GetSignalrResolver inside of NinjectWebCommon like this:
public static Microsoft.AspNet.SignalR.Ninject.NinjectDependencyResolver GetSignalrResolver()
{
return new Microsoft.AspNet.SignalR.Ninject.NinjectDependencyResolver(bootstrapper.Kernel);
}
Note: There are 2 different DependencyResolver: one for Web API (1) assigned to GlobalConfiguration.Configuration.DependencyResolver and the other for SignalR (2) assigned to GlobalHost.DependencyResolver
in order to use a dependency resolver for both WebApi and SignalR you need to implement a class that looks like this:
public class NinjectDependencyResolver : Microsoft.AspNet.SignalR.DefaultDependencyResolver,
System.Web.Http.Dependencies.IDependencyResolver
{
public readonly IKernel Kernel;
public NinjectDependencyResolver(string moduleFilePattern)
: base()
{
Kernel = new StandardKernel();
Kernel.Load(moduleFilePattern);
}
public override object GetService(Type serviceType)
{
var service = Kernel.TryGet(serviceType) ?? base.GetService(serviceType);
return service;
}
public override IEnumerable<object> GetServices(Type serviceType)
{
IEnumerable<object> services = Kernel.GetAll(serviceType).ToList();
if (services.IsEmpty())
{
services = base.GetServices(serviceType) ?? services;
}
return services;
}
public System.Web.Http.Dependencies.IDependencyScope BeginScope()
{
return this;
}
public void Dispose()
{ }
}
then in your startup class you should register NinjectDependencyResolver for both WebApi and SignalR, like this:
public void Configuration(IAppBuilder app)
{
var dependencyResolver = new NinjectDependencyResolver("*.dll");
var httpConfiguration = new HttpConfiguration();
httpConfiguration.DependencyResolver = dependencyResolver;
app.UseWebApi(httpConfiguration);
var hubConfig = new HubConfiguration { Resolver = dependencyResolver };
app.MapSignalR(hubConfig);
}
In my MVC project, I have setup my MvcApplication_start() :
ControllerBuilder.Current.SetControllerFactory(new NinjectControllerFactory());
And have successfully bound an .To regarding my IProductsRepository to MySqlProductsRepository:
public class NinjectControllerFactory : DefaultControllerFactory
{
private readonly IKernel _kernel = new StandardKernel(new MyServices());
protected override IController GetControllerInstance(System.Web.Routing.RequestContext requestContext, Type controllerType)
{
if (controllerType == null)
return null;
return (IController) _kernel.Get(controllerType);
}
public class MyServices: NinjectModule
{
public override void Load()
{
Bind<IProductsRepository>().To<MySqlProductsRepository>();
}
}
}
But I am using NHibernate, and have a separate Session Factory class that has a GetSession() method that returns an ISession.
public static ISessionFactory SessionFactory = CreateSessionFactory();
private static ISessionFactory CreateSessionFactory()
{
var cfg = new Configuration().Configure(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "nhibernate.config"));
cfg.SetProperty(NHibernate.Cfg.Environment.ConnectionStringName, System.Environment.MachineName);
NHibernateProfiler.Initialize();
return cfg.BuildSessionFactory();
}
public static ISession GetSession()
{
return SessionFactory.GetCurrentSession();
}
I wanted to set it up so that my MySqlProductsRepository would be passed and ISession object by Ninject when it was created:
public class MySqlProductsRepository : IProductsRepository
{
private readonly ISession _session;
public MySqlProductsRepository(ISession session)
{
_session = session;
}
And my Controller would be handed a IProductsRepository instance:
public class AdminController : Controller
{
private readonly IProductsRepository _productsRepository;
public AdminController(IProductsRepository productsRepository)
{
_productsRepository = productsRepository;
}
MY PROBLEM:
I can't seem to figure out in my IoC container where I bind my IProductsRepository to my Repository, how to register an ISession, how to hand an ISession to my MyProductsRepository object when it is created, and hand an MyProductsRepository object to my Controller?
I have a couple of blog post I wrote that explain how to use Ninject in and ASP.NET MVC application. The application in the blog post uses the same technologies that you are using: Ninject, NHibernate, and MySql. I also am using a repository pattern. There are a lot of parallels between what you are doing and these posts.
http://blog.bobcravens.com/2010/07/using-nhibernate-in-asp-net-mvc/
http://blog.bobcravens.com/2010/06/the-repository-pattern-with-linq-to-fluent-nhibernate-and-mysql/
http://blog.bobcravens.com/2010/09/the-repository-pattern-part-2/
http://blog.bobcravens.com/2010/11/using-ninject-to-manage-critical-resources/
Take a look. If you have questions, feel free to contact me.